docs: clarify region count wording in daily check (#21456)#21457

ti-chi-bot[bot] merged 4 commits intopingcap:release-7.5pingcap/docs-cn:release-7.5from

ti-chi-bot:cherry-pick-21456-to-release-7.5ti-chi-bot/docs-cn:cherry-pick-21456-to-release-7.5Copy head branch name to clipboard